Seam welding is the one type of resistance welding and also another modification of spot welding. The basic chief difference of spot weld and seam weld is that the formation of electrode. They are usually power driven and rotate whilst gripping the work. The current is supplied through the rotatable wheel and melt the metal. The edges of the two sheets must be overlap, so that the welding heat can be developed in joining interface of the sheet metal. The large manufacturing of cylindrical container, drum, pipe, etc. is best suited by these types of welding.
When the body is being performed into a
tube, the overlapping edge made in united piece which is called longitudinal welding and the end position fitted of assembly work weld is called circumferential welding.
The use of seam welding is mainly designated for the thin sheet metal, the sheet metal often welded which should not exceed 1/8 inch. The welding speed may vary with the sheet gauge. The special machines are employed for the faster welding speed. In the bellow diagram shown the basic principle of seam welding.
Generally two types of seam welding machines found 1) Circumferential Seam Welding Machine 2) Longitudinal Seam Welding Machine. They are called because of the types of welding joint performance. Although the Universal Seam Welding Machine can perform both operation. By the changing of electrode assembly the circumferential welding can be converted into longitudinal welding.
In the seam welding operation, the sheets to be welded are properly overlapped and positioned between the both rollers. The clamp may be provided for the holding properly and applying the pressure. A current is provided through rollers to the material contact with them. The sufficient heat is produced and material reached in plastic stage. The welding operation done by pressure applied with both rollers and applied current.
The another important factor with roller cooling efficient. The huge amount of heat is developed through the rollers, so its required sufficient cooling system, which is increase the life of roller electrodes. The removal of heat from region of the work the special type roller is used. Which is cooling system is provided. After a short period of use the edges of the electrodes require trimming, the trimming operating can not be obtained by filling operation. The trimming or re-